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The Slap Fingerprint Segmentation Evaluation 2004 (SlapSeg04) is an assessment of the accuracy of algorithms used to segment slap fingerprint images into individual fingerprint images.

·  Slap fingerprints (slaps) are taken by simultaneously pressing the four fingers of one hand onto a scanner or fingerprint card. Slaps are also known as four-finger simultaneous plain impressions.

·  Slap segmentation is the process by which a single image containing four fingerprint images is divided into four images of the individual fingers.

SlapSeg04 is being conducted by the National Institute of Standards and Technology (NIST) on behalf of the Department of Justice (DOJ) Justice Management Division (JMD), IDENT/IAFIS Integration Project.

The Final Report (NISTIR 7209) is now available:


A briefing on the results of SlapSeg04 was given at the U.S. Department of Justice on March 9th, 2005. The slides are available here:


Thirteen segmentation applications from ten organizations are being evaluated in SlapSeg04:


  • 123ID
  • Aware
  • Cogent
  • NEC
  • NIST
  • Sagem Morpho
  • Smiths-Heimann (SHB)
  • Sonda
  • UltraScan


SlapSeg04 will serve as part of NIST's statutory mandate under section 403c of the USA PATRIOT Act to certify those biometric technologies that may be used in U.S. VISIT.

The use of slap fingerprints for background checks is being considered in a variety of U.S. Government fingerprint systems (including U.S.VISIT and IAFIS). The segmentation of slap fingerprints is known to have an associated error rate, but no rigorous evaluation of current slap segmentation algorithms has ever been conducted. Knowing whether existing segmentation software is feasible for operational use will be of practical interest and value to policymakers.

Email contact: slapseg04@nist.gov.

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